Hammer mill provided with means for detachably mounting the sizing screen



WW 2% Wm I3. F. SCHUTTE ETAL 3,5322

HAMMER MILL PROVIDED WITH MEANS FORVDETACHABLY MOUNTING THE SIZING SCREEN Filed Sept. 15, 1948 2 Shams-Sheet 1 BNVENTORJS Char/e5 E Schultz and ATTORNEYS N c. F. SEIHUTTE FETAL 2W5 mmm MILL PROVIDED WITH MEANS FOR DETACHABLY MOUNTING THE SIZING SCREEN Filed Sept. 15, 1948 2 Sheets-Sheet 2 N2 M I & HNVENTORS d) Char/e: 'fi' Sam/tie and O N HY Herman Q Jammie Patented Nov. 28, 1950 HAMMER MILL PROVIDED WITH MEANS FOR DETACHABLY MOUNTING THE SIZ- ING SCREEN Charles F. Schutte, Bufialo, and Herman D. Schutte, Snyder, N. Y.

Application September 15, 1948, Serial No. 49,404

2 Claims. 1

This invention relates to screen mills as in the case of our earlier U. S. Patent No. 2,328,170, and more particularly to screen mills or pulverizers and to further improved means for mounting exchangeable screen members thereon.

One of the objects of the invention is to provide an improved pulverizer of the hammer mill type having improved means incorporated therein for mounting the product sizing screen member thereof.

Another object of the invention is to provide a mill of the character described having an improved form of product screening element which is adapted to be mounted and demounted with respect to the mill frame in an improved manner.

Another object of the invention is to provide in a mill of the character described improved means for detachably locking the product screening member in mounted position relative to the mill frame.

Another object of the invention is to provide a mill of the character described having an improved arrangement for quickly and easily exchanging product screening members thereof so as to grade the mill product to different specifications.

Another object of the invention is to provide a mill for the purposes set forth hereinabove wherein the procedure of exchanging the screen members thereof may be performed With improved safety and facility, without requiring the mill to be first shut down. Other objects and advan-- tages of the invention will appear in the specification hereinafter.

In the drawings:

Fig. 1 is a side elevation of a hammer mill of the invention with a portion of the casing broken away to show the interior thereof, and with the screen member thereof shown in both mounted and demountable positions;

Fig. 2 is a fragmentary top plan of the machine of Fig. 1; and

Fig. 3 is an enlarged view of a detail of Fig. 1, showing the screen positioning and latching mechanism in different positions of operation.

The drawings illustrate the invention in connection with a hammer mill of the type that is adapted particularly for grinding or pulverizing grain or other commodities, and the mill comprises essentially a box-like base or frame l carrying bearing blocks I2 at opposite sides thereof for rotatably supporting the rotor shaft 14. The rotor I6 is carried by the shaft l4 and in turn mounts a series of hammers l8 which are pivotally connected to the rotor so as to extend radially therefrom. Heads 20 are carried by the hammers I8 to receive the majority of the wear in connection with processing of the mill feed. An upper casing or cover portion 22 is mounted upon the base [0 so as to complete the mill enclosure, and a mill feed inlet spout 24 is arranged to discharge the mill feed through an inlet port 26 of the mill cover so as to discharge the mill feed in the form of a continuous stream into the mill casing and upon the rapidly rotating rotor and hammer unit while traveling in substantially the same direction of movement.

The end wall portion of the mill casing substantially opposite to the mill feed chute is preferably reinforced by a wearing plate 30 in the region of impingement of the mill feed stream against the casing wall resulting from the momentum of the mill feed and the impact of the rotor hammers thereagainst. Thus, the wearing plate 30 may constitute an integral portion of the mill casing wall 32, or may be simply a detachable wearing plate mounted therewithin so as to be renewed from time to time as may be required. The product screening element of the mill comprises an arcuately shaped screen member 34 such as a perforated sheet metal plate or a Woven wire fabrication, or the like; and the screen member is mounted to extend transversely of the mill frame structure l0 between opposite side wall portions thereof and so as: to complement and closely conform to the lower arc of the mill hammer orbit. Consequently, in the case of certain mills of the prior art the screen elements thereof corresponding to the member 34 of the present invention are arranged to be mounted relative to the other mill elements when in operative position so as to be disposed. in substantially the same manner of arrangement as is illustrated by the solid line showing thereof in Fig. 1 of the present drawing. However, the prior art arrangements usually involve in addition some provision for dropping the screen member downwardly away from operative position preliminary to removal of the screen member from the mill frame in connection with screen exchange procedures as are required to turn out products of various specifications. Such arrangements have invariably involved the use of relatively complicated screen support and exchange devices; the use of which usually requires the mill to be stopped before the screen members may be exchanged, and through use of which the time required for screen exchange is very substantial.

In the case of our prior patent we disclosed an improved arrangement accommodating with-1 drawal and replacement of screens through an opening at the front end of the mill, and removable means for levering and latching the screens in operative positions. The present invention provides further improvements in the screen manipulating and locking mechanisms in such mills.

As in the case of our prior patent, in accord with the present invention the opposite side wall portions of the base frame are provided with inwardly extending ledges which are of substantially circular form in side view and disposed concentrically of the center of rotation of the rotor-hammer unit. A second set of inwardly extending ledges 38 are arranged to extend inwardly from the side wall portions of the base frame and are arranged in substantial parallelism with and are relatively closely spaced relative to the corresponding ledges 3% in the region of the rear half of the mill. Thus, a relatively narrow space as indicated at 48 is provided between the corresponding ledge members 3t- 33 at each side of the mill in the rear portion thereof for slide-fitting reception of the corresponding side edge portions of the screen member 3t therebetween. Thus, it will be understood that in the rear portion of the mill the ledge members 3$5-8 at opposite side wall portions of the mill frame will cooperate to position the rear portic-n of the screen 34 in operative position and in an attitude of concentricity with respect to the axis of the rotor rotation.

At the forward end portion of the mill, however, the ledge members 3838 are formed so as to diverge further away from the positions of the corresponding ledge members at so as to provide a funnel-like space as indicated at 22 (Figs. 1 and 3) between corresponding of the ledges 3638 within which the corresponding end portion of the screen member 34 is free to move in directions radially of the axis of rotor rotation. The screen member 34 is formed to be of resilient nature and to have a tendency to set in a curvature having a radius substantially larger than the radius of the orbit of the hammer mill rotation.

Thus, any one of a number of screens such as the member 34% may be selected and mounted singly within the mill by initially disposing it in pick-a-back relation upon the casing wall 32 as illustrated by broken lines in Fig. 1. Then the lower end of the screen member is inserted into the funnel-like spaces between the ledges 35-38, whereupon the screen member may be slid downwardly and under the rotor hammer assembly as its leading end portion proceed rearwardly of the mill and is guided between the closely spaced ledges 3638 into its final operative position. Durin this initial installation procedure the trailing end portion of the screen 34 will of course bear away from the inner ledges 35-35, due to the tendency of the screen member to normally set at a curvature somewhat flatter than the curvature of the ledges 36. As will now be explained the screen positioning and locking mechanism of the invention is then brought into action to complete the installation of the screen member in operative position.

The positioning and locking member of the present invention differs from that of our prior Patent and comprises essentially a lever device including a transverse plate portion 58 having a looped handle 52 extending at a right angle therefrom. The forward edge of the plate 56 is formed with a beaded nose 5t so as to engage in roller bearing contact relation against the end portion of the screen. The plate of the locking device is formed at opposite sides with car portions 5858 which receive bearing pins 60-50 extending inwardly from the mill casing side Walls.

The lever l te and bearing pin elements are so constructed and arranged that when the plate 59 is pivoted as to the position thereof shown in Fig. 1 and the broken line position thereof in Fig. 3, the nose portion 54 thereof forcibly pushes against the upper end portion of the screen 34 so as to elastically deform the latter into contiguous conformity with the casing ledges 36 throughout the entire length of the screen. Thus, the screen is held by the lever plate 50 in screenoperative position. A latch 62 i pivotally mounted as at 64 to extend from a front cover plate portion 68 of the mill base ID, for latching the handle 52 in the position thereof shown in Fig. 1, thereby holding the lever plate 59 in its screen lockin position.

To release a previously mounted screen for re.- placement thereof whenever it is required to sub.- stitute another screen without requiring the mill to be shut down, it is only necessary to lift the latch 62 and to pull outwardly upon the lower end of the handle 52. The lever plate 55 there: upon pivots upon the pins (Bil-450, as to the solid line position of the lever plate shown in Fig. 3, whereupon the adjacent a d of the screen 34 will move into the funnel-like space between the opposed ledges 36-33 in response to the elastic forces of the screen material. The free end of the screen may then be grasped by the operator of the mill and the screen withdrawn by simply lifting it upwardly as to the broken line position thereof in Fig. 1, whereupon the screen may be removed completely from the mill and a substitute screen of generally similar form but having the required size of apertures may be inserted, as in the manner of mounting described hereinabove. It will be appreciated that a particular feature and advantage of the arrangement of the invention resides in the fact that due to the natural resiliency and tendency of the screen members to open to curvatures of greater diameter than the curvature of the mill rotor orbit when the screens are released from restraint against the ledges 36-36, the screen members will be thereby automatically adapted to move freely about the enlarged curvature of the end wall 32 of the mill casing. Qtherwise, the screen members would clamp and wedge against the end wall 32 of the casing in such manner as to prevent the mounting and dismounting procedure as described hereinabove. It will also be appreciated that the screen positioning and locking meehe anism of the invention provides, in combination with the other elements of the device, an imp v d method nd ea for quickly and positively positionin and locking the screen in operative position upon the mill, and for quickly releasing the screen in connection with dismounting operations; and that the entire screen exchange procedure may be accomplished in only a few seconds while the mill rotor is kept running. Thus, there is a substantial saving of time and motor restarting power which would otherwise be lost in connection with the screen changing process.

A further important feature of the present invention resides in the provision of a guard plate 1!! which comprises a curved metal sheet shaped, t mp meni the curvature of the ass ing cover plate portion 30 and to normally lie externally thereagainst as illustrated by the solid line showings thereof in Figs. 1-3. The plate 16 is vertically slotted as indicated at '52 to accommodate a bolt M which extends from the cover plate 32 and carries a wing nut '15 for locking the plate in various positions of vertical adjustment relative to the cover plate 32. The slot through the guard plate 16 is arranged so that following release of the screen as to the solid line positions thereof in Fig. 3, the wing nut 75 may be loosened so that the guard plate will drop down into the opening 12, such as to the broken line position of the guard plate 70 as shown in Fig. 3. This plate thereupon functions as a barrier against accidental access by the operators hand to positions within reach of the mill hammers, incidental to operator manipulation of the released screen and/or installation of a substitute screen as explained hereinabove. Then, upon completion of a subsequent installation of a substitute screen into the solid line position thereof in Fig. 3, the guard plate 76 Will be retracted to its raised position and the lever handle 52 then depressed so as to force the screen to contract into operative position against the ledges 3S; whereupon the lever handle 52 will be locked by the latch 62 and feeding of the mill continued.

It will also be appreciated that in view of the novel arrangement and operation of the machine of the invention the screen exchange process may be conducted without possibility of danger to the operator of the machine, and with utmost facility and convenience to the operator thereof in every respect; and that although only one form of the invention has been shown and described in detail, it will be apparent to those skilled in the art that the invention is not so limited but that various changes may be made therein without departing from the spirit of the invention or the scope of the appended claims.

.What is claimed is:

1. In a sizing mill, a bottom frame, a rotor mounted upon said frame for rotation within a circular orbit, a semi-cylindrical screen mounted upon said frame to substantially complement the lower half of said rotor orbit, said screen being elastic and having a tendency to normally set in a curvature having a radius substantially greater than the radius of said rotor orbit, a top cover mounted upon said bottom frame to complete enclosure of said rotor at the upper side thereof, said cover being shaped to generally conform to the orbit of said rotor and divergent from the curve of said frame at one end to provide a screen change opening therebetween, ledge means extending from said bottom frame to slidably receive and locate one end portion of said screen so as to be in operating position coaxial with said rotor orbit, said ledge means being adapted to limit centripetal displacement of said screen throughout its entire extent to a cylindrical operating position coaxial with said rotor orbit, and lever means including a handle and a mill closure plate hingedly mounted upon said frame to engage said screen at the other end portion thereof, said mill closure plate being formed with a screen engaging portion for slide bearing engagement against said screen for elastically deforming said screen into said operating position by clamping said other end portion of said screen upwardly and centripetally into said operating position against the elastic forces of said screen, and a locking device associated with said handle for detachably locking the latter in screen operating position, whereby said screen may be mounted in operating position within said mill by disposing it in inverted attitude upon said top cover and then sliding said screen down- Wardly and under said rotor into engagement with said ledge means at the rear end of said mill, and then levering the trailing end portion of said screen into constricted curvilinear form as limited by said ledge means against the elastic force of said screen into a coaxial attitude With respect to said rotor orbit and locking said screen in said operating position by means of said locking device, and a guard plate, operable mounting means for mounting said guard plate on said top cover, said mounting means being so constructed and arranged as to permit said guard plate to be moved from its normal position on said cover and clear of said screen change opening down to a position extending between said rotor orbit and. the released position of said other end portion of said screen.

In a sizing mill, a bottom frame, a rotor mounted upon said frame for rotation within a circular orbit, a semi-cylindrical screen mounted upon said frame to substantially complement the lower half of said rotor orbit, said screen being elastic and having a tendency to normally set in a curvature having a radius substantially greater than the radius of said rotor orbit, a top cover mounted upon said bottom frame to complete enclosure of said rotor at the upper side thereof, said cover being shaped to generally conform to the orbit of said rotor and divergent from the curve of said frame at one end to provide a screen change opening therebetween, ledge means extending from said bottom frame to slidably receive and locate one end portion of said screen so as to be in operating position coaxial with said rotor orbit, said ledge means being adapted to limit centripetal displacement of said screen throughout its entire extent to a cylindrical operating position coaxial with said rotor orbit, and lever means fulcrum-mounted upon said frame to engage said screen at the other end portion thereof and adapted to be actuated manually for levering said other end portion of said screen against the elastic forces thereof into said operating position coaxial With said rotor orbit, and locking means associated with said lever means for detachably locking the latter in operating position, and a guard plate, operable means for mounting said guard plate on said top cover clear of said screen change opening but permitting said guard plate to be slidable substantially vertically thereon into said screen change opening subsequent to release of said lever locking means and expansion of said screen toward said normal set curvature.

CHARLES F. SCHUTIE. HERMAN D. SCHUTTE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,307,761 Shelton June 24, 1919 1,679,182 Shelton July 31, 1928 1,752,971 Ammon et al. Apr. 1, 1930 1,947,700 Elzemeyer Feb. 20, 1934 2,012,416 Bartels Aug. 27, 1935 2,076,297 Gray Apr. 6,. 1937 2,328,170 Schutte et al. Aug. 31, 1943 2,419,773 Gruendler Apr. 29, 1947 

